DPL: improve helpers for function / lambda reflection

Optimization of ROOT streaming of MCLabelContainer

Using custom streamer for MCTruthContainer<MCCompLabel> and flatten the two
vectors into one additional char vector member before serialization. The original
vectors are empty during serialization. When reading an object, the vectors are
restored from the char vector which has been streamed.

The reduced serialization time for one single char vector and two empty vectors outweighs
the cost of flattening and restoring. There is a significant speedup in the serialization.

As the next step, for transmitting messages the serialization can be skipped completely
by a custom DPL IO interface implementation for MCTruthContainer.

TODO:
- add move assignment from a source vector, by that passing an object which has access to
  different underlying memory resources, until that, the pmr::MemoryResource has been
  removed again
- add interface to access header and truth elements directly from the raw buffer, by that
  inflation can be postponed until new elements are added, with the effect that inflation
  can be avoided in most cases. This avoids copy for deserialized read-only objects.

Fix: account for diff.spans of response and sensor depths

Code owners (AliceO2Group#2357)

* Initial reasonable filling of CODEOWNERS file

Remove broken & unneeded otool command.

Applying completion and dispatch policies to process individual TPC s…

…ectors

Configure all processes to dispatch data immediately, clusterer and decoder
processes process the sector data is they come in. This reduces to amount of data
which are hold in parallel in the pipelines.

Re-enable "Streamline DPL Allocator::snapshot" after update of InputR…

…ecord

This reverts commit 13a5d10.

Re-enable "Streamline DPL Allocator::snapshot" after update of InputR…

…ecord

This reverts commit 13a5d10.

Re-enable "Streamline DPL Allocator::snapshot" after update of InputR…

…ecord

This reverts commit 13a5d10.

Provide missing dictionary for CPVSimParams